H. A. Nurrizky, C. U. Wirawati, S. Surfiana, and D. E. Nirmagustina, “Formula Optimization and Characterization of Soybeans and Pearl Millet (Penisetum glaucum) Tempeh Using Simplex Lattice Design Methods”, IFSTJ, vol. 8, no. 2, pp. 229–235, Jul. 2025.